Mechanism for operating switches



May 25, 1943. s; H. DURBIN MECHANISM FOR OPERATING SWITCHES Filed 001;. 28, 1941 INVENTOR 1573/ /15) H BU FE/A/ BY M l' ATTORNEYJ Patented May 25, 1943 UNITED STATES PATENT OFFICE MECHANISM FOR OPERATING SWITCHES StanleyHIDu rbin, Brooklyn, N. Y., as'signo'r to E. W. Bliss' Company, Brooklyn, N. Y., a corporation of Delaware Application October 28, 1941, Serial No. 416,802

3 Claims.

the switch 52 by moving the said plunger downwardly against the force of a spring (not shown) which coacts with said plunger to hold it yieldably in its uppermost or inoperative position.

The substantially closed upper side ll of the drum l5 has an outwardly extending boss l8 through which is formed an. air passage l9, threaded toward its outer end as at 20 to afford means for connecting 'an' air line' thereto, and having at its inner end an aperture 2!, preferably of reduced diameter, afiording passage for air from such an airline, into the drum 15.

In mounting the drum l5 upon the base plate ll, an annular spacing gasket 22"of suitable pressure. thickness is placed betweenthe diaphragm l6 Another object of this invention is the proviand the baseplate to afford space therebetween sion of a switch-operating mechanism which, for the flexing of the diaphragm to an extent whiie fully responsive to sustained pressure somewhat more than sufiicient to' enable the lat changes. nevertheless, is not operatively responter to operate the switch; and an annular sealsive to momentary pressure changes. ing gasket 23 of'suitable'sealing material is placed Another object of this invention is the provibetween th diaphragm Iii and the adjacent botsion of a switch operating mechanism which may tom surface of the body of the drum l5 to provide easily b adjusted to respond to air pressure an air-tight connection therebetween. The bolts changes. 15a preferably should be tightened sufiiciently to Still another object of-this invention is the 25 prevent slippage of the diaphragm and said gasprovision .of a switch operating mechanism which kets relatively to the base plate and 'drum and is simple in structure and capable of long and relatively to each other; constant use without requiring repairs or re The switch I2 is preferably so mounted'that it placement of parts. may readily be adjusted to a proper operating re- These and other objects and advantages may lationship-with respect to the diaphragm 12. To be derived from the present invention of which, this purpose, the switch may be mounted within for purposes of illustration, a preferred embodi-' a rigid yoke 24 by means of screws 25, and the ment is disclosed in the accompanying drawing, yoke may be carried upon adjusting screws 26 in which extending through each end of said yoke, thence Figure l is a central sectional view of a prethrough compression coil 'springsil, and threadferred embodiment of the invention, arbitrarily ed into holes 28, provided therefor'in the base positioned with an air drum and air connections plate II. The said springs normally urge the at the top and the electric switch and electric yoke 25 into coaction with the-heads of the adconnections at the bottom: lusting screws 26 and, by screwing the latter in Fig. 2 is a plan view of the embodiment, look- 40"or out as necessary, the switch l2 may be ading'down upon the air drum; and justed to the precise position in which the plung- Fig. 3 is a view looking up to the portion houser' I3 thereof will coact properly with the diaing the electric switch and connections, the housphragm It during fle g of the latter to operate ing being partly broken away to show the switch said switch. Once'this adjustment is attained, mounting. the frictional engagement of the'thread'ed por- The mechanism is built up about a rigid base tions of the adjusting screws 26within' the holes plate ll, upon the under side of which is adjust- 28 may suiiice to maintain the adjustment. An ably mounted an electric switch [2 having an acadditional assiu'ance of the maintenance of this tuating plunger [3 extending through an aperadjustment may be derived by th use of lock tiu'e M in said base plate, and upon the upper washers 29 disposed on the adjusting screws 28 side of which is secured, by means of bolts [5a, an air drum l5 having a diaphragm l6, preferably in the form of a thin metal disc which is positioned'adjacent' the free end of the plunger oover screws 3 l'.

between the heads of the latter and the yoke 24.

The switch is preferably enclosed by a cover 3!], suitably fastened, to'the base plate H as by The cover, with the base plate,

IS andadapted',when'slightly flexedto operate B5 forms an enclosure 32 for said switch and a.

threaded opening 33 is provided in the base plate to afford means for connecting thereto an electric conduit from within which electric wires (conduit and wires not shown) may pass into said enclosure for connection to terminals 34 of the switch. The cover, of course, may be easily removed to permit adjustment of the switch and connection of wires thereto and the interior of the said enclosure may be suitably insulated.

In practice, the mechanism may be connected, at the threaded portion 20 of the passage iii, to an air line, the pressure within which is desired to operate said mechanism. When so connected, the switch may be employed to control a circuit in apparatus adapted to restore air pressure in said air line if such pressure has increased or decreased beyond permissible limits; or said switch may be used to open or close or otherwise modify a circuit adapted to control apparatus which actuates or which may prevent actuation of a machine in which the mechanism is employed; or it may be used both to control the restoration of pressure in said air line and to control the operation of such a machine while such restoration of pressure is in progress. The mechanism may also be put to other uses than those mentioned herein,

The disc selected for use as the diaphragm is, ordinarily, should be of such thickness and other characteristics that it will fiex to the proper extent, under the pressure and pressure variations to which it may be subjected in the use in which it is to be employed, to move the plunger l3 sufficiently to operate the switch l2.

In one mode of operation, it may be assumed that the air pressure normally present in the air line to which the device is connected and, consequently, present within the drum l5 either will not flex the diaphragm l6 materially or will flex it only slightly downwardly as viewed in Fig. 1. Upon the establishment of such normal air pressure within the drum iii, the position of the switch I2 may be adjusted by suitable turning of the adjusting-screws 26 to bring the end of the plunger [3 (then yieldably held in its inoperative or normal position) into intimate juxtaposition to the center of said diaphragm. Then, upon any increase of pressure in the drum, beyond permissible or predetermined limits the diaphragm will flex downwardly or the flexing thereof will increase to cause it to engage and press the plunger l 3 downwardly to an extent suflicient to operate the switch l2. When the air pressure drops back to normal, the diaphragm unflexes to permit the plunger I3 to move outwardly to its inoperative position. The efiective movement of the plunger in such a switch may be very slight as, for example, 0.001" so that a relatively slight pressure variation will cause suflicient flexing of the diaphragm to operate the switch.

If it is desired to have the switch I2 operate as a result of a decrease in air pressure, the characteristics of the diaphragm l6, preferably, should be such that normal air pressure will cause material downward fiexing of the diaphragm and the adjustment of the position of the switch should then bring the end of the plunger I3 in engagement with the center of the diaphragm with the plunger in depressed position, which, in the switch employed in this arrangement may be said to be its inoperative position. Any drop in air pressure would then diminish the flexing of the diaphragm and permit the plunger to move upwardly under the force of its actua in p in to 745 chamber and to coact with said plunger whereby operate the switch. Other modes of operation of the mechanism may also be arranged.

Although it is suggested that the characteristics of the diaphragm l6 may be selected with particular reference to the pressures involved, the device, with a selected diaphragm, may nevertheless be employed to respond to pressures extending over a relatively wide range in view of the means for the substantial adjustment provided in the switch mounting.

The size of the aperture 2| has a material efiect upon the operation of the device. By making said aperture relatively small in cross-sectional area, momentary pressure variations in the air line to which the device is connected, produce little or no variation in the pressure within the drum l5 and, hence, the switch is operated only by somewhat sustained pressure variations. On the other hand, said aperture may be made relatively large, so that even momentary pressure variations in the air line would be reflected instantly within the said drum and the switch would respond either to momentary or sustained pressure variations. The determination of the size of said aperture depends, of course, upon the manner in which the switch is desired to function in the particular machine in which it is employed.

It will be understood that the inventive concept may be employed in various ways other than those disclosed herein without departing from the invention as defined in the accompanying claims.

What I claim is:

1. An operating mechanism for a switch having a reciprocable actuating member, said mechanism comprising a mounting piece, a rigid air drum fixed upon said mounting piece, means for connecting the interior of said drum with a controlling air source located exteriorly thereof, a diaphragm airtightly secured upon said drum to form, with the latter, an air chamber, and means for holding such a switch upon'said mounting piece with its actuating member in operating rela-tionship relatively to said diaphragm whereby said switch may be actuated by movement of its actuating member in response to flexing of the diaphragm caused by air pressure variations within said air chamber, the said switch-holding means being adjustable whereby to permit adjustment of the position of the switch relatively to the diaphragm, the said switch-holding means comprising a rigid member adapted for carrying said switch, a screw coacting with said member and said mounting piece to positively move said member and the switch carried thereby toward said diaphragm, and resilient means coacting with said rigid member and opposing movement of said switch toward said diaphragm.

2. In combination, an electric switch having an actuating plunger, a mounting plate having an opening extending therethrough, adjustable switch-holding means adapted to hold said switch upon one side of said plate with the said plunger extending through said opening, a diaphragm mounted upon the other side of said plate with a flexible portion thereof disposed adjacent the free end of said plunger, a rigid air drum fixed upon said plate in air-tight connection with said diaphragm and forming, with the latter, an air chamber, and means for connecting the interior of said chamber with a separate controlling air source, the said diaphragm being adapted to flex in response to variations in air pressure in said to move the latter and operate the switch, and the switch-holding means comprising a rigid member upon which the switch is fixed, and two or more screws coacting with difi'erent portions of said member and threaded into holes in said plate, the said screws being restrained against longitudinal movement relatively to said member and being adapted, by screwing them inwardly and outwardly relatively to said plate, to effect adjustment of the position of the switch relatively to the diaphragm.

3. In combination, an electric switch having an actuating plunger, amounting plate having an opening extending therethrough, adjustable switch-holding means adapted to hold said switch 15 diaphragm and forming, with the latter, an air chamber, and means for connecting the interior of said chamber with a separate controlling air source, the said diaphragm being adapted to flex in response to variations in air pressure in said chamber and to coact with said plunger whereby to move the latter and operate the switch, and the switch-holding means comprising a rigid member upon which the switch is fixed, two or more headed screws extending through said member at different points thereon and threaded into holes in said plate, and compression springs extending about the shanks of said screws, the ends of the springs pressing against said plate and said rigid member whereby to hold the latter against the screw heads and constrain the said member and the switch thereon to move toward or away from the diaphragm as the said screws are turned inwardly or outwardly with respect to the mounting plate.

STANLEY H. DURBIN. 

